O'Shea is one of the few people in the world who have succeeded in keeping not only coastal but also deep-sea squid alive in captivity. Unlike an octopus, which, as he put it, "you can't kill, no matter how hard you try," a squid is highly sensitive to its environment. Accustomed to living in a borderless realm, a squid reacts poorly when placed in a tank, and will often plunge, kamikaze-style, into the walls, or cannibalize other squid.

In 2001, during a monthlong expedition at sea, O'Shea caught a cluster of paralarval giant squid in his nets, but by the time he reached the docks all of them had died. He was so distraught that he climbed into the tank, in tears, and retrieved the corpses himself. "I had spent every day, every hour, trying to find the paralarvae, and then they died in my grasp," he told me. For two years, he was so stricken by his failure that he refused to mount another expedition. "I knew if I failed again I would be finished," he recalled. "Not just scientifically but physically and emotionally."

He couldn't stop wondering, though, about what had happened in the tank. His wife, Shoba, a computer scientist who was born in India, told me that sometimes in the middle of an unrelated conversation he would suddenly say, "What did I do wrong?" O'Shea became determined to correct what he called "my fatal mistake," and began a series of painstaking experiments on other species of juvenile deep-sea squid. He would subtly alter the conditions of captivity: tank size, intensity of light, oxygen levels, salinity. He discovered that the tank in which he had stored his paralarvae during the expedition had two lethal flaws: it had a rectangular shape, which, for some reason, caused the squid to sink to the bottom and die; and its walls were made of polyethylene, a plastic compound that, it turns out, is toxic to deep-sea squid. "Knowing what I know now, I feel like a fool," he said. "It was like walking them to their execution."